demo: fix example_basic plugin (#5366)

* Replace old multiplexer with data provider (`MultiplexerDataProvider`) and make related changes.
* Add Description column

tensorboard/examples/plugins/example_basic/tensorboard_plugin_example/plugin.py

@@ -18,8 +18,9 @@
 import json
 import os
 
+from tensorboard import plugin_util
+from tensorboard.data import provider
 from tensorboard.plugins import base_plugin
-from tensorboard.util import tensor_util
 import werkzeug
 from werkzeug import wrappers
 
@@ -35,17 +36,15 @@ def __init__(self, context):
         Args:
         context: A base_plugin.TBContext instance.
         """
-        self._multiplexer = context.multiplexer
+        self.data_provider = context.data_provider
 
     def is_active(self):
         """Returns whether there is relevant data for the plugin to process.
 
         When there are no runs with greeting data, TensorBoard will hide the
         plugin from the main navigation bar.
         """
-        return bool(
-            self._multiplexer.PluginRunToTagToContent(metadata.PLUGIN_NAME)
-        )
+        return False  # `list_plugins` as called by TB core suffices
 
     def get_plugin_apps(self):
         return {
@@ -69,16 +68,18 @@ def _serve_js(self, request):
 
     @wrappers.Request.application
     def _serve_tags(self, request):
-        del request  # unused
-        mapping = self._multiplexer.PluginRunToTagToContent(
-            metadata.PLUGIN_NAME
+        ctx = plugin_util.context(request.environ)
+        experiment = plugin_util.experiment_id(request.environ)
+
+        mapping = self.data_provider.list_tensors(
+            ctx, experiment_id=experiment, plugin_name=metadata.PLUGIN_NAME
         )
-        result = {run: {} for run in self._multiplexer.Runs()}
-        for (run, tag_to_content) in mapping.items():
-            for tag in tag_to_content:
-                summary_metadata = self._multiplexer.SummaryMetadata(run, tag)
+
+        result = {run: {} for run in mapping}
+        for (run, tag_to_timeseries) in mapping.items():
+            for (tag, timeseries) in tag_to_timeseries.items():
                 result[run][tag] = {
-                    "description": summary_metadata.summary_description,
+                    "description": timeseries.description,
                 }
         contents = json.dumps(result, sort_keys=True)
         return werkzeug.Response(contents, content_type="application/json")
@@ -92,16 +93,23 @@ def _serve_greetings(self, request):
         """
         run = request.args.get("run")
         tag = request.args.get("tag")
+        ctx = plugin_util.context(request.environ)
+        experiment = plugin_util.experiment_id(request.environ)
+
         if run is None or tag is None:
             raise werkzeug.exceptions.BadRequest("Must specify run and tag")
-        try:
-            data = [
-                tensor_util.make_ndarray(event.tensor_proto)
-                .item()
-                .decode("utf-8")
-                for event in self._multiplexer.Tensors(run, tag)
-            ]
-        except KeyError:
+        read_result = self.data_provider.read_tensors(
+            ctx,
+            downsample=1000,
+            plugin_name=metadata.PLUGIN_NAME,
+            experiment_id=experiment,
+            run_tag_filter=provider.RunTagFilter(runs=[run], tags=[tag]),
+        )
+
+        data = read_result.get(run, {}).get(tag, [])
+        if not data:
             raise werkzeug.exceptions.BadRequest("Invalid run or tag")
-        contents = json.dumps(data, sort_keys=True)
+        event_data = [datum.numpy.item().decode("utf-8") for datum in data]
+
+        contents = json.dumps(event_data, sort_keys=True)
         return werkzeug.Response(contents, content_type="application/json")

tensorboard/examples/plugins/example_basic/tensorboard_plugin_example/static/index.js

@@ -27,6 +27,7 @@ export async function render() {
             run,
             tag,
             greetings,
+            description: tagToDescription[tag].description,
           }))
       )
     )
@@ -61,16 +62,18 @@ export async function render() {
         createElement('th', 'Run'),
         createElement('th', 'Tag'),
         createElement('th', 'Greetings'),
+        createElement('th', 'Description'),
       ])
     ),
     createElement(
       'tbody',
-      data.flatMap(({run, tag, greetings}) =>
+      data.flatMap(({run, tag, greetings, description}) =>
         greetings.map((guest, i) =>
           createElement('tr', [
             createElement('td', i === 0 ? run : null),
             createElement('td', i === 0 ? tag : null),
             createElement('td', guest),
+            createElement('td', description),
           ])
         )
       )

tensorboard/examples/plugins/example_basic/tensorboard_plugin_example/summary_v2.py

@@ -62,4 +62,5 @@ def _create_summary_metadata(description):
             plugin_name=metadata.PLUGIN_NAME,
             content=b"",  # no need for summary-specific metadata
         ),
+        data_class=summary_pb2.DATA_CLASS_TENSOR,
     )